Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Microfeatures I'd like to see in more languages

buttondown.email

Post reply on HN
Print view View original

171–180 of 539 posts

Re: Microfeatures I'd like to see in more languages

#171

Post by dariusj18 »

turtledragonfly wrote: post #2

With regard to strings, they give a good example in Lua, but oh boy wait until this person hears about Perl (: There's a whole section in the manual [1] for string quoting operators (qq, qw, qx, ...) In general, I feel like Perl is one of those languages that has a high amount of these "quality of life" syntactic features, and helps make it enjoyable to write, once you get over the learning curve. [1] https://perldoc…

That's actually a great point. Perl has so many syntactic sugars that it is a poster child for too much variety in ways you can write things. Making it much harder to read someone else's code.

Re: Microfeatures I'd like to see in more languages

#172

Post by masklinn »

tobyhinloopen wrote: post #148

Elixir’s testing library uses meta programming to show the code that fails and what the values were at both sides of a comparison. IE a = 1; b = 2 assert a == b Will fail with error like: Assertion failed, a == b Left is 1 Right is 2 So you don’t have a bunch of assert-functions; you just assert anything and it will spit out a decent error.

With how old pytest is, I assume that's where they got it from. Does it perform recursive value printing, or bespoke comparisons?

e.g. in pytest it won't just print out the values of "a" and "b", it will recursively document intermediate values until it's reached the toplevel expression:

    assert f() == g()
    assert 42 == 43
      where 42 = .f at 0xdeadbeef0002>()
      and   43 = .g at 0xdeadbeef0003>()
and it's possible to customise the report so you can report as a diff:

    assert "foo 1 bar" == "foo 2 bar"
      - foo 2 bar
      ?     ^
      + foo 1 bar
      ?     ^

Re: Microfeatures I'd like to see in more languages

#174

Post by masklinn »

elcritch wrote: post #156
masklinn wrote: post #149

Earlier quoted context omitted.

> The first time it's seen in any environment, it thread-safely inserts-if-not-present the default value into a key-value storage That seems like a great way to get amazingly hard to replicate bugs or odd behaviours if different subsystems use different values for the default.

You'd just need to have a mutex lock on the values. That could be slow, but you probably don't want to have a config flag in a hot loop anyways. :) In Nim you can do compile flags which let you set constants so you avoid the problem: const myLibraryVersion {.intdefine.} = 3

> You'd just need to have a mutex lock on the values.

Oh no they're saying that it's thread-safe, that's not an issue. Rather that depending on the order of initialisation, possibly of different systems entirely, you can have different initial states because different systems or subsystem decided of the default value.

Re: Microfeatures I'd like to see in more languages

#175

Post by maxbond »

ludston wrote: post #146
maxbond wrote: post #68

Earlier quoted context omitted.

Totally true. I don't know if IDEs commonly have a feature like, "find this value, regardless of how it's expressed" (even better yet, fuzzily, to catch typos), but I think that's the proper general solution. It's a good idea to consider a constants file earlyish, while everything still fits in your head. I'd say in the case of such a sprawling system, make a constants module, and it can have different files for diff…

When your code-base reaches a certain size, you cease using the IDE to find code and instead start using specialized tools, such as Lucene indexes so that grepping through code takes seconds rather than minutes. One of the bads of this is that using regex over an index is O(n) in comparison to the O(log(n)) of a normal index lookup.

Perhaps this special tooling can normalize numbers and other source code ambiguity.

Re: Microfeatures I'd like to see in more languages

#176

Post by mncharity »

amalgamated_inc wrote: post #45

Elixir's sigils are amazing. There are date sigils that allow you to do what the OP does: ~N[2023-01-01 12:00:00] But you can also define your own sigils to create new "custom syntax" for almost any struct. Kind of a special case of reader macros, I guess. Very convenient.

Elixir sigils[1][2].

Eg: ~w(foo bar bat) is a word list. `~ letter bracketed-text lettersasmodifiers` desugars as sigil_(text,modifiers). Similar to foo_str() of Julia[3], but for one-letter-names and more brackets. But not the unicode brackets of Raku.

[1] https://elixir-lang.org/getting-started/sigils.html [2] https://hexdocs.pm/elixir/main/syntax-reference.html#sigils [3] https://docs.julialang.org/en/v1/manual/metaprogramming/#met...

Re: Microfeatures I'd like to see in more languages

#177

Post by dan-robertson »

devmunchies wrote: post #147

# Function Shorthand #### I like how functions in js can be `arg => result`. In F# I have to do `fun arg -> result` with the `fun` keyword. It makes sense since `MyArgType -> MyResType` is a type signature in f#, but I feel like the compiler can just check if the arguments are references to types or are argument bindings. # Multiline Lists/Arrays #### I like how F# doesn't require delimiters for multiline lists. So I…

The function syntax I like even more is one with implicit arguments so you don’t have to name them, e.g.

  waiting = sum workers #(%.in_queue + %.in_flight)
Clojure has some syntax like this though it isn’t needed for the most obvious use-case of functions to extract fields because keywords, which are usually used for map keys, are implicitly functions that look themselves up in their arg, e.g.

  (:bar { :foo 3, :bar 2 })  ; => 2

Re: Microfeatures I'd like to see in more languages

#178

Post by _a_a_a_ »

Doctor_Fegg wrote: post #47

Negative array subscripts. So a[-1] means the last element of an array, a[-2] means the second last, and so on.

As a choice then perhaps but as a default and unalterable behaviour it can be a bloody timewaster when negative subscripts are a runtime error in your work. I've hit that in python and didn't enjoy it.

Re: Microfeatures I'd like to see in more languages

#179

Post by masklinn »

devmunchies wrote: post #147

# Function Shorthand #### I like how functions in js can be `arg => result`. In F# I have to do `fun arg -> result` with the `fun` keyword. It makes sense since `MyArgType -> MyResType` is a type signature in f#, but I feel like the compiler can just check if the arguments are references to types or are argument bindings. # Multiline Lists/Arrays #### I like how F# doesn't require delimiters for multiline lists. So I…

> I feel like the compiler can just check if the arguments are references to types or are argument bindings.

1. this is absolutely terrible because now you need feedback from the type checker to know how to parse the program

2. it is furthermore also ambiguous with function application, requiring arbitrary lookahead to disambiguate, also not a fun thing to do

JS gets away with it because the sigil was not previously used and it only requires a single lookahead to parse, as only single-parameter anonymous functions can have "bare" parameter lists.

Re: Microfeatures I'd like to see in more languages

#180

Post by _a_a_a_ »

feoren wrote: post #79
Doctor_Fegg wrote: post #47

Negative array subscripts. So a[-1] means the last element of an array, a[-2] means the second last, and so on.

Any language that supports overriding the index operation should support this. You should be able to do this in C# with a struct with a backing array, for instance. If you're going to do this, use the word "Circular" in it, and I would also insist that if a has 4 elements, then a[0] == a[4] == a[8]. In other words, you always just take the (positive) index modulo the size of the area. Then a[-1] is the same as a[N-1]…

What 'mod' is for, innit.
Post reply on HN